In the past 200 years the CO2 level in our atmosphere has risen from 280 ppm, which is near the high for the past 400,000 years, to 370 ppm, a level significantly higher than it has been through the last four ice age cycles. Two thirds of this rise has occurred over the last fifty years, and is strongly correlated with our burning of fossil fuels. At the same time, there has been a sharp rise in the average temperature of the surface of our oceans by about 0.7C, which seems strongly correlated with the rise in CO2 levels. This ‘global warming’ has caused most of the world’s glaciers to begin melting back at an accelerated pace, and led to partial melting of the Antarctic ice shelf and an accelerated movement of Antarctic ice toward the oceans. It has also allowed meltwater on the Greenland icecap to be propagate through the icecap to its base.

With the economic development underway in India and China, it is clear that, if we do not significantly lessen our dependence on fossil fuels as the major source of energy, the increase in atmospheric CO2 levels will continue to accelerate. The consequences of such a rise are unclear, but it seems plausible that ultimately the Antarctic and Greenland ice caps would melt, raising the level of the oceans and flooding major cities and farmland worldwide. At least some models suggest that this melting might in turn bring on another ice age. For example, if the Gulf Stream which transports heat to the Northern Atlantic were to shut down it could lead to more snow and lower temperatures in Northern Europe, thereby lessening the solar energy absorbed by the Earth. If we are just to keep the CO2 levels below 500 ppm within the next 50 years, we must embark now on a broad and concerted effort to replace fossil fuels with alternate sources of energy, including solar, wind, and nuclear energy, to conserve energy, and to sequester the CO2 produced by the burning of fossil fuels. Failure to do so will most certainly put the future of civilization as we know it in jeopardy.